Process of stabilizing oils



Oct. 27, 1936. A. LAZAR ET AL 2,058,696

PROCESS OF STABILIZING OILS Filed Feb. 27, 1954 \W N\ v /5 I l7 I /Z INVENTO/(S ,1 Y K m ab /71 TTORNE).

Patented Oct. 27, 1936 PATENT OFFICE PROCESS OF STABILIZING OILS Arthur Lazar, Associated, and mm Manderson Evans, Berkeley, 'Calif., ,assignors to Associated Oil Company, San Francisco, Calif., a corporation of California Application February 27, 1934, Serial No. 713,180

Claims.

This invention relates to a process of stabilizing oils and is particularly directed to the treatment of lubricating oils wherein great stability against heat is provided, as well as an improved appearance in color, such improvements being largely due to the elimination of constituents which cause instability, and specifically relate to the separation of asphaltic bodies from oils which have been subjected to the herein disclosed treatments.

In the preparation of lubricating oils which may be subjected to intense heat during service, such as in an internal combustion engine, it has been found practically essential to prevent, or minimize, cracking of such oils, to the end that their physical characteristics may be maintained.

An objectof this invention is to produce lubricating oils of the highest stability. This may be accomplished by refining oils in such a manner that the unsaturated and aromatic hydrocarbons are removed or have been protected by the addition of an extremely stabilized solution specially prepared as hereinafter described.

It is a wellrknown fact that refining oils with liquid $02, as in the Edeleanu process, separates aromatic and unsaturated hydrocarbons. This leaves a saturated oil which has extreme stability when subjected to heat and oxidation.

Such saturated hydrocarbons are best suited for lubrication as industrial oils, motor oils, etc. At the same time decomposition under great heat is diflicult to prevent, particularly in lubricating oils which have been refined by an acid treatment such as sulphuric acid, where some of the unsaturated hydrocarbons are left in the oils.

It is a further object .of this invention to add a highly stabilized and saturated hydrocarbon solution to less refined acid treated oils, the presence of this solution tending to prevent decomposition of unsaturated compounds which are present in these oils.

This invention is applicable to the treatment of lubricating oil refined by either method for the purpose of increasing, stability therein, but a much superior prcduct'results from its appli,-

cation to oils refined with liquid sulphur dioxide. I

In treatments to iproduce lubricating oils-oi. high stability, it is very desirable to produce such oils with a distinguishing and pleasing appearance so that a particular oil ofproven high stability-may be identified.

[By the use of this process; it'is found that m only is the desired high stability imparted totheoil but at t e same time a marked green l c-v rescence is added-to lubricating oils which otherwise are lacking in the same.

Referring to the single drawing, an inclined ,retort II) is placed ma furnace H and heated by a burner H, to the end that a gas oil, or the like, which is fedthrough a pipe it, will be maintained in motion in film form.

The heat supplied from burner i2 is of adegree to cause destructive decomposition of the oil fed through pipe 13, to the end that there is but a small amount of carbon, or coke, left in retort It, the remaining products of decomposition passing in gaseous form through conduit it to be condensed in condenser l6, whence they flow in liquid form to a receiver ill, from which they may be withdrawn through valve i8.

' Any incondensable gases may be withdrawn through pipe IQ for use in any manner and such coke as remains in retort ill, being a minimum quantity and practically valueless, may be removed therefrom from time to time.

" The product recovered in liquid form in receiver I1 is the starting point for material used in this invention and from this material are derived certain hydrocarbons which, when treated and added to a body of refined lubricating oil,

such as described, give the desired stability to,

the oil and impart a marked green fluorescence thereto.

The liquid in receiver l'l comprises a mixture of light and heavy hydrocarbons which may be separated by fractional distillation and which may be used as such a mixture, or as bottoms after such distillation, to'stabilize a body of treated lubricating oil, preferably an S0: treated oil, and impart a marked green fluorescence rial in the mixture undissolved, the desired hydrocarbons being of particularly high stability due to the excessive heat treatment under which they are formed andhaving the characteristic of imparting such stability to a. lubricating oil with which they may be mixed in desired proportions. r

The solvent oil preferred for such extraction is one which has been tfeatecf with liquid. sulphur dioxide and comprises only highly saturated mixed with the liquid mixture from receiver I1 in about the proportion of 9:2.

The light constituents of the combined mixture are then distilled off in any well known manner with fire and open steam, starting with very little steam and increasing the same gradually mitil the original flash of the lubricating oil in the mixture is restored. The remaining bottoms may then be separated by sedimentation, skimming, or filtration, to yield a clear oil which is the stabilized product desired for adding to a body of lubricating oil for increasing its stability.

Likewise, the desired stabilized hydrocarbons from the liquid mixture in receiver I] may be obtained by fractionally distilling the mixture to remove the lighter hydrocarbons therein, after which an S02 treated lubricating oil of approximately 200 viscosity, S. U. at 100 F. is mixed with the bottoms in the still in about the proportion of 9:1 and heated up to about 400 F. A moderate amount of steam may be used to carry over any residual light fractions and the distillation is continued until the flash of the solvent lubricating oil is restored, at which time a clear oil is likewise separated by sedimentation, skimming, or filtration, to be added in the desired amount to a body of lubricating oil for stabilizing the same.

A solvent oil of other viscosity within reasonable limits may be used, provided such solvent oil is one comprising saturated hydrocarbons resulting from treatment with liquid sulphur dioxide, it having been found that solvent oil derived from an oil treated with sulphuric acid exercises a far too great solvent power for the asphaltic "compounds in the liquid mixture from receiver I1, and therefore the stability of a lubricating oil to which it may be added will be lessened, due to the decomposition of such asphaltic compounds when later the lubricating oil is subjected to intense heat treatment, such as in an engine.

The desired solvent oil derived from the S02 treatment of a lubricating oil having the desired viscosity is preferably added to theliquid mixture from receiver l1 prior to distillation thereof, because, apparently, the presence of light hydrocarbons in the mixture first causes the asphaltic compounds therein to be almost completely dissolved in the solvent oil. Thereafter, during distillation, the asphaltic and other undesired compounds will precipitate gradually in proportion with the removal of the lighter constituents, leaving the desired stabilized hydrocarbons in solution and in this manner a more complete separation and solvent action is insured.

In either case, a clear oil freeof asphaltic compounds and containing the desired stabilized hydrocarbons is recovered to be blended with lubricating oils to primarily improve their stability, but which likewise improves their appearance.

The lubricating oils tobe improved are preferably S02 treated oils but may be oils which have been treated with H2804, and the clear stabilizing oil described'may be added thereto as from 1% to 20% of the lubricating oil, even a small percentage having a noticeably favorable effect on stabilizing quality andcolor.

An alternative methodof blending includes the addition of either the clear stabilizing oil described or the bottoms obtained by reduction of the mixture in receiver II to a body of lubricating oil prior to its treatment with S02 or H2SO4.

In this case the removal of undesirable asphal tic compounds and hydrocarbons is brought about by the treating agent used, @However, in-

asinuch as this form of treating generally causes higher losses, its application is less to be recommended.

It is quite clear that the solvent oil used for the extraction of stabilizing" hydrocarbons from oil decomposition products, whether overhead or residual stock, may be a portion of the body of lubricating oil which is to be stabilized, provided that the lubricating oil has been subjected to treatment with liquid sulphur dioxide and is therefore a highly saturated oil.

The primary destructive distillation of' an oil in retort i0 is generally known as the Pintsch gas process, but a stabilizing oil may also be derived from coal tar, water gas tar, or other like materials, which represent an overhead distillate from the decomposition under heat of coal, bituminous materials, or oils. Highly saturated hydrocarbons exercise similar selective dissolving properties on these tars in the same manner as on the distillate in receiver l1.

However, an overhead distillate obtained as described is a more desirable material for this invention than the distillate derived from the above mentioned materials, on account of the complete absence of certain undesirable non-hydrocarbons classified under the name of creos0tes".

While the above described process is specificially applicable to products of the so-called Pintsch gas process, yet the scope of the invention broadly covers a much larger range of materials which yield the desired stabilizing products having a desired fluorescence, provided the solvent extraction oil is of saturated character.

For instance, the raw materials to be processed for the extraction of desired hydrocarbons include: residua from heat treating process such as cracked residua, petroleum coke, coal tar residuum, brown coal tar residuum, residuum from the destructive distillation of carbohydrates such as cellulose and the like, and residua from polymerization processes utilizing chemicals such as zinc chloride, aluminum chloride, ferric chloride or boron fluoride.

Such raw materials should be digested with a saturated hydrocarbon oil, which may be selected from practically the whole range of mineral oils, such as gasoline, kerosene, or lubricating oils derived from a crude oil of paraffin base origin and which are naturally of a highly saturated character, or liquid S02 treated mineral oils of all boiling ranges regardless of their origin, or solvent treated mineral oils regardless of their origin, or mineraloils which have been saturated by special processes such as hydrogenation, or synthetic mineral oils of saturated character.

The use of such oils of saturated character for extracting the desired compounds includes digesting the raw material for a predetermined period of time preferably with predetermined heat and agitation accompanied by separation of asphaltic compounds, or coke, by settling, filtration, etc., and separation of undesired light fractions by distillation, as above described.

The solvent oil thus obtained, freed from asphaltic compounds and containing the desired stabilizing hydrocarbons, may then be added to a lubricating oil, which has preferably been treated with liquid S02 but which may have been treated with H2504, in the proportions already described.

It will thus be noted that the herein described process provides for a transfer agent which has the property of extracting certain desired hydro carbons from raw materials and transferring the same while in dissolved condition to alubricating sired asphaltic compounds.

Such transfer agent is found to be a highly saturated 'oil,"preferably one which has been treated with liquid S02, and the utilization of such clearly distinguishesfrom the prior art in leaving asphaltic compounds undissolved; other solvent oils derived from a distillate treated with sulphuric acid retain a portion of asphaltic compounds dissolved. This is. highly undesirable because, with lubricating oils used in internal combustion engines, eventhough such dissolved asphaltic compounds be present in minute quantities their decomposition in such engines is inevitable and the decomposition products thereof are cumulative to the point of excessive coky deposits in the engine with consequent increased wear and deterioration.

This application is a continuation in part of our copending application Ser. No. 478,870, filed August 30, 1930.

We claim as our invention:

1. The process of stabilizing oils and imparting a green fluorescencethereto which comprises: reducing a material containing hydrocarbons of high stability and green fluorescence until .a residuum is obtained, mixing with said residuum a solvent oil above the boiling range of kerosene and of such highly saturated character and so substantially free from aromatic and unsaturated hydrocarbons that said contained hydrocarbons are readily soluble therein but asphaltic compounds are insoluble therein whereby said hydrocarbons of high stability are dissolved while substantially all asphaltic compounds in the mixture remain undissolved toan extent that further deasphaltizing treatment is not required, separating out undissolved compounds, and adding a portion of the remaining mixture to a lubricating oil.

2. The process of stabilizing oils and imparting a green fluorescence thereto which comprises: reducing a material containing hydrocarbons of high stability and green fluorescence until a residuum is obtained, mixing with said residuum a solvent oil above the boiling range of kerosene and of such highly saturated character and so substantially free from aromatic and unsaturated hydrocarbons that said contained hydrocarbons are readily soluble therein but asphaltic compounds are insoluble therein whereby said hydrocarbons of high stability are dissolved while substantially all asphaltic compounds in the mixture remain undissolved to an extent that further deasphaltizing treatment is not required, separating out undissolved compounds, and adding a portion of the remaining mixture to a highly saturated lubricating oil.

3. The process of stabilizing oils and imparting a green fluorescence thereto which comprises: reducing a material containing hydrocarbons of high stability and green fluorescence until a residuum is obtained, mixing with said residuum a solvent oil above the boiling range of kerosene and of such highly saturated character and so substantially free from aromatic and unsaturated hydrocarbons that said contained hydrocarbons are readily soluble therein but asphaltic compounds are insoluble therein whereby said hydrocarbons of'high stability are dissolved while substantially all asphaltic compounds in the mixture remain undissolved to an extent that further deasphaltizing treatment is not required, distilling the mixture to recover an unvaporized fraction therefrom of desired flash and viscosity,,sep.- arating out said undissolved compounds, and adding said fraction to a lubricating oil of about the same flash and viscosity.

4. The process of stabilizing oils and imparting a green fluorescence thereto which comprises:

reducing a material containing hydrocarbons of high stability and green fluorescence until a residuum is obtained, mixing with said'residuum a solvent refined solvent oil above the boiling range of kerosene and of such-highly saturated character and so substantially free from aromatic and unsaturated hydrocarbons that said contained hydrocarbons are readily soluble therein but asphaltic compounds are insoluble therein whereby said hydrocarbons of high stability. are dissolved while substantially all asphaltic compounds in the mixture remain undissolved to an extent that further deasp'haltizing treatment is not required, distilling the mixture to recover an unvaporized fraction therefrom of desired flash and viscosity, separating out said undissolved compounds, and adding said fraction to a lubricating oil of about the same flash and viscosity.

5. The process of stabilizing oils and imparting a green fluorescence thereto which comprises: mixing a residuum, obtained from the conversion of hydrocarbon oils and containing hydrocarbons of high stability and green fluorescence, with a highly saturated solvent oil above the boiling range of kerosene substantially free from unsaturated and aromatic hydrocarbons and having less selectivity for asphaltic compounds in said residuum than a solvent oil which has been treated with H2304 whereby said high stability hydrocarbons are dissolved while substantially all asphaltio compounds in the mixture remain undissolved to an extent that further deasphaltizing treatment is not required, separating out said undissolved compounds and adding a portion of the remaining mixture to a lubricating oil.

6. The process of stabilizing oils and imparting a green fluorescence thereto which consists in mixing a residuum, obtained from the conversion of hydrocarbon oils and containing hydrocarb'ons of high stability and green fluorescence, with a saturated solvent oil above the boiling range of kerosene and which has been treated with liquid S02 having less selectivity for asphaltic compounds in said residuum than a solvent oil which has been treated with H2804 whereby said high stability hydrocarbons are dissolved while substantially all asphaltic compounds in the mixture remain undissolved, reducing said mixture to a desired viscosity, separating out said undissolved compounds and adding said mixture to a lubricating oil.

7. The process of stabilizing oils and imparting a green fluorescence thereto which consists in mixing a residuum, obtained from the conversion of hydrocarbon oils and containing hydrocarbons of high stability and green fluorescence, with a saturated solvent oil above the boiling range of kerosene and which has been treated with liquid S02 having less selectivity for asphaltic compounds in said residuum than a solvent'oil which has been treated with H2804 whereby said high stability hydrocarbons are dissolved while substantially all asphaltic compounds in the mixture remain undissolved, reducing said mixture to a desired viscosity, separating out said undissolved compounds, and adding said mixture toa saturated lubricating oil which has been treated with liquid S02.

8. The process of preparing a stabilizer against oxidation and heat for hydrocarbon lubricating oils, which consists of mixing with the distillate from a decomposition process of the nature of the Pin'tsch gas process, a solvent oil or carrying agent comprising a highly refined lubricating oil substantially free from aromatic and unsaturated hydrocarbons, and of the order of 200 viscosity S. U. at 100 F., distilling the mixture as a whole in order'to volatilize oils lighter than said lubricating oil and separating solid products out of the remaining mixture, thereby leaving a clear stabilizing oil. a

9. The process of claim 8 in which the carrying agent is mixed with the distillate in about the proportion of 2 to 9.

10. A process of preparing a stabilizer against oxidation and heat for hydrocarbon lubricating oils, which comprises: subjecting a hydrocarbon oil of the nature of gas oil to a decomposition temperature, recovering distillates therefrom, mixing with said recovered distillates a carrying agent comprising a highly refined lubricating oil substantially free from aromatic and unsaturated hydrocarbons, and of about 200 viscosity S. U. at 100 F., distilling the mixture as a whole in order to volatilize oils lighter than said lubricating oil and separating solid products out from the remaining mixture thereby leaving a clear stabilizing oil.

ARTHUR LAZAR.

JOHN.MANDERSON EVANS. 

